It is known from time to time that human operators such as maintenance engineers or the like need to access areas near machinery which can be hazardous. For example where heavy machinery has moving parts a human operator must be protected to avoid falling into the moving parts or to accidentally locate a limb in a hazardous region. The problem is exacerbated by the fact that certain maintenance operations can take prolonged periods of time when concentration levels can wane. Conventionally protective measures have merely focussed on defining hazardous regions and clearly demarcating regions where an operator can or cannot go. However since maintenance can take place over prolonged periods of time when concentration levels can drop such mere demarcation has sadly on occasion proved inadequate.
Escalators in public or private areas are an example of heavy machinery which can provide hazardous environments to operators.
The escalators along with their supporting truss framework are situated and hidden below ground or floor levels where the public go about their daily business. Escalators are often arranged in pairs or multiples in a side by side arrangement. The gap between escalators in these chambers is at best the width of an average operative with many being much narrower.
Escalators are very powerful machines that run at full speed and torque for the majority of each day and every day of the week with only minimum non-operational time permitted. Access to these areas is rigorously controlled with strictly no permitted access allowed to the areas between escalators whilst one or more are operating.
As a consequence conventionally the only time unrestricted access is permitted is during the hours the escalator is out of action. For example, at a station, there is typically a maintenance window of between 01:00 hrs and 05:00, after closure, and prior to the station reopening to the public. Repairing an escalator during this window of opportunity is often not feasible and often results in the machine remaining non-operational for much longer than desired.
Also many other scheduled events need to be carried out on the escalator during these short available night periods such as routine maintenance and cleaning operations. With the advent of 24/7 services in certain locations such as is anticipated with the London Night Tube, where certain tube lines and stations will operate on a 24 hour basis, the time slots currently available will no longer be an option.